Why can stone sculptures break when carved too thinly?

Stone sculptures are prone to breaking when carved too thinly because stone is extremely heavy and lacks tensile strength.1

While stone exhibits great compressive strength—meaning it can bear significant weight—it is a brittle material that fractures easily when subjected to stress or tension. When a sculptor carves stone into thin, delicate, or projecting forms, the material cannot effectively support its own weight or withstand external pressures, leading to breakage unless it is properly supported.12

In contrast, materials like wood possess a fibrous structure that provides considerable tensile strength, allowing for thinner and more open designs. Similarly, metals such as bronze have high tensile strength, which permits much greater freedom of design and attenuation of form without the same risk of fracture. Because of these physical limitations, traditional stone sculpture often favors massive, compact treatments without vulnerable projections.1